title: Observations on historical, contemporary, and natural PCDD/Fs.
mesh_terms: D001572:Benzofurans / Q000032:analysis / Q000266:history* / Q000378:metabolism; D001711:Biotransformation; D000072338:Dibenzofurans, Polychlorinated; D004784:Environmental Monitoring; D049672:History, 19th Century; D049673:History, 20th Century; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000032:analysis / Q000266:history* / Q000378:metabolism; D012016:Reference Values; D012989:Soil Pollutants / Q000032:analysis / Q000266:history* / Q000378:metabolism
chemical_list: D001572:Benzofurans; D000072338:Dibenzofurans, Polychlorinated; D000072317:Polychlorinated Dibenzodioxins; D012989:Soil Pollutants